Tach going to 1000 when car is shut off

[JasonC]

I probably already know the answer to this (SI batteries). But today this just started, that when I shut my car off the tach returns to 0 like it should but soon after it jumps up to 1000. While running everything works like it should. But the SI lights go off after about a min of running. They been doing that for about a year now. I did take the cluster apart and everything looked clean.

Just wanting to reconfirm my thoughts on it being the batteries or maybe something else.

[dnguyen1963]

Did it jump to 1000 after shutting off and stay there? I agreed that the SI batteries are most likely the cause, but I would also clean all the grounds on the main board to prevent any arcing.

[Mwishlist]

I replaced mine trying to run down a tach issue which turned out to be a waterlogged ECU. It was cheap and easy. You can get a pair on ebay for about $30.

[zaq123]

....... waterlogged ECU. .

interesting....

is it you?

https://youtu.be/Koxzz7LDmEE

[JasonC]

Yeah it jumps up and says there till I start the car and then it reads like it should. I was looking on eBay at batteries, will pick some up here.


Also interested in how the ecu got waterlogged lol.

[Mwishlist]

interesting....

is it you?

https://youtu.be/Koxzz7LDmEE

[JasonC]

Well the batteries should be here tomorrow. But the tach stopped doing the nonsense it was doing... Still will replace them since they are the originals from 92.